1. Field of the Invention
The present invention relates generally to methods for achieving superior bonds between synthetic elastomers and metals and, specifically, to a method for achieving a superior bond between silicone rubber compositions and metals.
2. Description of the Prior Art
Various techniques are known in the art for adhering silicone rubber to metal surfaces. The normal technique for adhering silicone rubber to a metal member is to subject the metal member to a phosphating treatment prior to priming the metal member and contacting the member with the silicone rubber. The phosphating technique involves one or more hot alkali dip and rinse cycles, followed by a phosphate dip and rinse cycle. Good bonds can be obtained if the phosphate level is correct. However, if the phosphate concentration in the phosphate dip is too low or too high, poor bonds result.
Another prior art technique for preparing metal surfaces for bonding to silicone rubbers is sand blasting. Using this technique, the metal surface is silica sand blasted to remove scale, corrosion, and other foreign matter. The sand blasting technique is a cleaner process than phosphating but results in bonds of variable quality. The process is also labor intensive.
There exists a need for a method for forming an improved bond between silicone rubber and metal surfaces which consistently produces reliable bonds, which is not labor intensive, and which is an easy and clean process.